I call an external API from my JAVA app, the API is from another app (Let’s call it App2), App2 is deployed on Test environment, the API hit error [sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target, javax.net.ssl.SSLHandshakeException] when I run my app locally as well as when I deployed to Test environment. However, the API works when I deployed to Sit environment, so I was suspecting something wrong with Test environment but I have no idea what is the issue.